Above the western holy gates of the monastery, facing the Sera River, is the church of the holy great martyr Theodore Stratilates. The temple was consecrated in honor of the heavenly patron of the monastery's founder, Tsar Fyodor Alexeyevich, and was built in the last year of his life. This is evidenced by the inscription in the iconostasis above the image of the Savior: "Heavenly King, strengthen our righteous king and Grand Duke Fyodor Alexeyevich, affirm the faith, bring peace, and preserve this holy abode well." The first antimension of the church, sent from Moscow, was consecrated on May 15, 1682, after the death of the tsar. The builder of the church, Elder Cornelius, did not live to see the consecration. In his memory, the image of the martyr archdeacon Euplus was depicted on the southern deacon's door, on the day of whose memory Father Cornelius passed away.

The church, located above the holy gates, is part of the western wall of the brick enclosure of the monastery. The central part of the church stands out with its high volume compared to the northern and southern porches, each crowned with a drum topped with a dome and cross. The eastern facade, facing the monastery, is adorned with windows with blazing frames and a tier of zakomaras. The western facade, facing the river, features narrow high loophole windows and is decorated with a light arcature belt, characteristic of the architecture of Vladimir-Suzdal Rus. Inside, each part of the church is covered with vaults with metal ties, the central part rises on two steps, and the floor was made of brick. To the west of the holy gates, a white stone platform was arranged. In the central arch, there were double wooden doors with paintings: "the image of the Lord Almighty with the Most Holy Mother of God and John the Baptist and the apostles, painted on the gates is the Last Judgment, and on the right and left walls are painted the archangels Michael and Gabriel," according to the inventory of 1764. In the side arches, there were two passage gates. In the early 19th century, the southern arch, which also had a staircase to the church, was bricked up, the church was reinforced with buttresses, the wooden roof was replaced with an iron one, and the mica windows were replaced with glass ones. At the entrance to the church, in the recess of the enclosure, there was a miraculous Kazan icon of the Mother of God with an unquenchable lamp since the 17th century. In 1923, the church was closed, but in 1992, with the revival of the monastery, it was returned to the community. After restoration and the installation of a new iconostasis in 1993, the church was consecrated anew. Now, night Liturgies, confessions, and monastic tonsures take place there. Next to the gates, a stone cell known as the "guard tent" was built. For some time, the venerable Cornelius lived there, who later moved to a house outside the monastery walls but continued to come here to communicate with the sisters. Later, the cell was inhabited by gatekeeper nuns. Now the cell of the venerable Cornelius has been restored, and a small exhibition on the history of the monastery is displayed at the entrance.